The Site and Planting Density Effects on the Wood Volume Growth of Chinese Fir Plantations in South Subtropical Area
The Site and Planting Density Effects on the Wood Volume Growth of Chinese Fir Plantations in South Subtropical Area
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DOI：
10.13275/j.cnki.lykxyj.2019.04.003
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发表时间：
2019-08-01
期刊：
影响因子：
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通讯作者：
Zhang Jian-guo
中科院分区：
文献类型：
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作者：
Guo Guang-zhi;Duan Ai-guo;Zhang Jian-guo
【目的】为杉木高效培育提供理论与实践依据，研究立地和种植密度对中国南亚热带地区杉木人工林林分材积生长规律的影响。【方法】基于广西大青山杉木人工林36年的定位观测数据，包括5种种植密度，即1667株·hm⁻²（A）、3333株·hm⁻²（B）、5000株·hm⁻²（C）、6667株·hm⁻²（D）和10000株·hm⁻²（E），分析了总材积和活立木材积的动态变化。【结果】种植密度和立地对总材积和活立木材积生长的影响是一致的。在中幼龄阶段，总材积与林分种植密度和立地指数呈明显正相关。种植密度和立地指数越高，总材积越大，且15年后中等密度林分的总材积远大于其他林分。总材积平均年生长量（MAT）先快速增加，达到峰值后下降，密度越高，下降开始得越早且越明显。总材积连年生长量和平均年生长量达到峰值的林分年龄分别为第10年和第14年，总材积生长率在19 - 25年时下降到3%。【结论】立地指数对种植密度相对较低林分总材积的影响较大，但随着种植密度的增加，这种影响变弱。如果以最大材积为培育目标，在立地指数为16时，密度C是最合适的种植密度。中国南亚热带地区的首次间伐、最后间伐和主伐年龄应分别在约10年、14年和25年左右。主伐年龄不应早于19年，种植密度越低，主伐越晚，A和B密度林分的主伐可推迟到25年。
[Objective] To provide theoretical and practical basis for the efficient cultivation of Chinese fir, the effects of site and planting density on stand wood volume growth rules of Chinese fir (Cunninghamia lanceolata) plantations in south subtropical area of China were studied. [Method] Based on 36-year positioning observation data of Chinese fir plantations in Daqingshan, Guangxi, including five planting densities, i.e. 1 667 trees . hm(-2)(A), 3 333 trees . hm(-2) (B), 5 000 trees . hm(-2)(C), 6 667 trees . hm(-2)(D) and 10 000 trees . hm(-2) (E), the dynamics of total wood volume and living trees wood volume were analyzed. [Result] The effects of planting density and site on the growth of total wood volume and living trees wood volume were consistent. The total wood volume was obviously positively related to stand planting density and site index during middle and young ages. The higher the planting density and the site index were, the bigger the total wood volume became, and the total wood volume of stand with medium density became much bigger than the other stands after 15 years. The mean annual increment (MAT) of total wood volume increased rapidly at first and then declined after reaching to the peak, and the higher the density was, the earlier the decline started and more obvious it became. The stand ages at which the current annual increment, and the MAT of total wood volume reached to its peaks were at the 10th and 14th years, respectively, and the growth rate of total wood volume decreased to 3% at the age of 19 similar to 25. [Conclusion] The influence of site index on total wood volume of stands with relatively low planting density is greater, but with the increasing of planting density, the influence becomes weak. If the maximum wood volume is taken as the cultivation target, density C is the most suitable planting density at the site index of 16. The first thinning, last thinning and final cutting in south subtropical area of China should be at about 10, 14, 25 years old, respectively. The final cutting should not be earlier than 19 years old, the lower the planting density is, the later the final cutting will be, and the final cutting of the stands with density A and B can be postponed to 25 years old.